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Asbestos Rubber Sheets — Oil & Chemical Resistance Explained (Optimized translation & rewrite; includes common aliases: asbestos gasket sheets, oil-resistant asbestos rubber sheets, and asbestos-reinforced rubber sheets.)
1. Short conclusion — don’t confuse “oil-resistant” with “resistant to everything."Asbestos rubber sheets that resist oil are not invincible. After ten Before you order, always ask: what temperature, what oil, and is there water? Don’t buy based only on the label “oil resistant.”
Base polymer (rubber type)
Nitrile rubber (NBR) content is important. Only sheets that contain 35% NBR or more can bear the label “oil resistant.” We classify sheets with less than 30% NBR as “short-term oil contact” grade. Our standard Aohong formula uses 40% NBR — ASTM No. 3 oil at 100 °C for 70 h gives ≤ 8% volume swell, well below the 12% national limit.
Asbestos fiber grade
Short-fiber Canadian asbestos (CF-4) holds the best strength. Its tensile retention is 85% or more after soaking in oil. Long-fiber South African asbestos costs less. But, it absorbs about 15% more oil and is more prone to blistering.
Curing/crosslinking system
Peroxide plus secondary cure (like PbO and dicumyl peroxide) creates a denser crosslink. This keeps oil molecules from getting through. Conventional sulfur cure gives shorter crosslinks; under hot oil, the rubber softens quickly.
| Oil type | Temp | Soak time | Thickness swell | Weight gain | Surface condition |
|---|---|---|---|---|---|
| #0 Diesel | 70 °C | 168 h | +2.1% | +1.8% | No blistering |
| 92# Gasoline | 23 °C | 168 h | +12% | +9.5% | Sticky at edges |
| SAE 15W-40 engine oil | 100 °C | 168 h | +3.4% | +2.9% | Slight hardening |
| Transformer oil | 80 °C | 168 h | +1.9% | +1.5% | No change |
| Aviation kerosene | 60 °C | 168 h | +8.7% | +6.2% | Surface fuzzing |
Interpretation: high-aromatic fuels (gasoline, kerosene) cause the most swelling; diesel, engine oil and transformer oil are generally safe for NBR-based asbestos rubber sheets.
Alkaline water (pH > 11): asbestos fibers hydrolyze — strength can drop by 50% in three months. In alkaline service, switch to non-asbestos aramid fiber sheets.
**Strong acids (e.g., 10% H₂SO₄ or 5% HCl):** NBR can’t handle acids. You'll see surface fuzzing in 24 hours at room temperature. So, use fluoroelastomer (FKM) sheets that are non-asbestos for acidic media.
Ethylene-glycol antifreeze: 100 °C for 168 hours → sheet hardens, compression recovery drops to 15%, and sealing fails.
Remedy: increase rubber content to 50% NBR or use non-asbestos alternatives.
Refrigerant R134a: It’s fine in vapor at room temperature. But at high temperatures, fluorine ions can form. These ions may attack the asbestos-rubber interface, causing cracks. So, consider using FKM sheets for hot R-gas exposure.
In 2023, a refinery in Shandong used an oil-resistant asbestos gasket sheet. This was in the vacuum and alkaline wash area. The pH was 13, and temperatures hit 90 °C. In two months, gaskets powdered and leaked. The reason? 38% asbestos fiber leached out and caused the rubber matrix to collapse. The plant switched to FKM + aramid non-asbestos sheets, and the leaks stopped. Moral: don’t use asbestos sheets where strong alkali and high temperatures coexist.
| Medium | Temp | Recommendation |
|---|---|---|
| Diesel, engine oil | ≤100 °C | Asbestos rubber sheet, NBR 40% |
| Gasoline, kerosene | ≤60 °C | Short-term OK; for long term use non-asbestos aramid |
| Alkaline water (pH >11) | ≤80 °C | Do not use asbestos — use aramid fiber sheet |
| Strong acids | ≤60 °C | Do not use asbestos — use FKM (fluoroelastomer) sheet |
| Ethylene glycol | ≤100 °C | Increase rubber fraction to 50% or use non-asbestos |
| Refrigerants | Ambient | OK; high-temp exposure → use FKM |
Before buying an asbestos gasket sheet (or gasket), ask yourself three questions:
What type of oil will you use?
What’s the temperature?
Is there water involved?
If any answer shows >100 °C, alkaline, or strong acid, switch to non-asbestos or FKM. A single shutdown can be much more expensive than the price difference. Our warehouse has NBR-40% and NBR-50% grades. The thickness ranges from 0.5 to 5.0 mm. We can slit and die-cut on the same day. Emergency orders ship in three days.
Make a careful choice. First, ask about the oil type, temperature, and moisture. Decide if you need an asbestos rubber sheet or a safer non-asbestos option.
